The goal of this project is to use structure-based design strategies to develop inhibitors for protein and RNA targets that are essential for B. anthracis survival and infection. Identification of new targets will be performed in Projects 1 and 2. The initial target will be the glutamate racemase enzyme, which converts L-Glu to D-Glu, and which other studies have shown to be an essential enzyme for bacillus survival. Additionally, B. anthracis utilizes D-Glu as an essential building block of the peptidogiycan layer in its cell wall, which, in turn protects the bacilli from macrophage destruction during infection. Thus glutamate racemase inhibitors will potentially exhibit direct antibiotic action, and weaken capsule formation, compromising its ability to resist macrophage destruction. In preliminary work we have isolated the gene, expressed the enzyme in amounts suitable for assays, and have developed an assay for inhibitor discovery. We now propose to utilize a combination of high throughput screening, development of focused libraries for second generation screening, computer-based design of new inhibitors, and chemical improvement to develop high potency inhibitors with properties favorable for becoming drug candidates. Successful development has the potential to provide a highly potent anthrax-specific therapeutic. In collaboration with Projects 1,2 and 4, we propose to use a structured development plan for taking initial screening leads through an enhancement process to generate candidate therapeutic leads suitable for in vivo animal testing. Over the course of this project, we anticipate developing 4-8 new candidates for in vivo testing based on the foundation of lead discovery resulting from Projects 1,2 and 4.